Quantum Error Correction Using a Distance Three Surface Code with Superconducting Qubits.

Quantum error correction (QEC) is essential for executing large-scale quantum algorithms with high fidelity. A promising approach to QEC is based on the surface code, as it requires only local connectivity and has a high error threshold. In this talk, we present our progress towards the operation of a distance d=3 surface code consisting of 17 superconducting qubits. We verify the performance of the subsystems of the device by preparing logical states on four d=2 subsets of the full code using error detection [C. K. Andersen et al., Nat. Phys. 16, 875–880 (2020)]. We can then characterize the performance of the d=3 surface code by measuring the logical operator expectation values after one or several error correction cycles. We compare the logical states obtained when postselecting on no detected errors to the states from a minimum weight perfect matching error decoder that identifies and corrects for errors based on the syndrome measurements.